avone, bought in theme forest, haha, i need the developer's help

Yes, I look for the app for a long time last night, and I checked with shopify customer service just now, he said that this can be achieved by coding it to the theme liquid of the website

I need an APP that displays a discount code below the item that customers can copy directly. This way customers will know very clearly that I have a discount, and they won't miss out on it.